1. Field of the Invention
This invention relates to endoscopic surgical instruments. More particularly, the present invention relates to a surgical endoscopic biopsy forceps device having detachable proximal handle and distal portions.
2. State of the Art
Endoscopic surgery is widely practiced throughout the world today and its acceptance is growing rapidly. In general, endoscopic surgery involves the use of a camera or magnifying lens inserted through a tube, while a cutter, dissector, or other surgical instrument is inserted through another tube for purposes of manipulating and/or cutting an internal organ or tissue under view of the surgeon. In endoscopic biopsy procedures, typically, the camera is located in one lumen of a flexible endoscope while the biopsy cutter is placed through another lumen thereof.
By 1996, it is expected that more than two million additional endosurgeries will be performed per year that, in 1990, were done via open surgery (MedPRO Month, I:12, p.178). The advantages of endoscopic surgery are clear in that it is less invasive, less traumatic and recovery is typically quicker. As a result, many new instruments and devices for use in endosurgery are introduced every year. Most endoscopic instruments have similar configurations with a proximal handle, an actuation mechanism, and distal end effectors coupled by a tube through which the actuation mechanism extends. (As used herein, "proximal" means closest to the surgeon and farthest from the surgical site, while "distal" means farthest from the surgeon and closest to the surgical site.) The end effectors take many forms such as grippers, cutters, forceps, dissectors and the like.
Initially, endoscopic surgical instruments were very expensive, partly because they must be very small but still durable and reliable and the materials and manufacturing methods necessary to provide these features are expensive. Recently, however, a number of "disposable" endoscopic instruments have been introduced and their use is now widely accepted. One of the advantages of disposable endoscopic instruments over reusable instruments is that because they are used only a single time, there are no sterilization problems, (i.e., no risk of cross-contamination between patients) and no concerns about the dulling or nicking of blades or wearing of parts. However, in order to justify disposing of instruments after a single use, the instruments have to be much less expensive than the reusable tools. In order to manufacture the instruments less expensively, the disposable instruments therefore use less expensive materials. As a result, the disposable instruments potentially are less durable than the reusable instruments. It is recognized, however, that the less durable components of the disposable instruments are most often parts of the distal end effectors and that the proximal handle portion of a disposable instrument is substantially as durable as the proximal handle portion of a reusable instrument. Moreover, the distal end effectors are not so fragile that they can only withstand a single use. Despite manufacturer's recommendations to the contrary, some surgeons will sterilize disposable instruments and reuse them a few times in order to reduce "per procedure costs". Ultimately, however, it is the distal portion of the instrument which wears or breaks and mandates disposal of the entire disposable instrument.
Among the disposable endoscopic instruments in use today are a number of different types of biopsy forceps devices. These devices most often include very sharp opposing jaws for grasping and tearing tissue for biopsy. The jaws are mated with one another about a clevis pin which is mounted in a clevis. The clevis extends into a housing which is crimped to the distal end of a relatively long flexible coil. The proximal end of the coil is coupled to a handle having means for articulating the jaws. The handle generally includes a central slotted shaft about which a spool is disposed. A pull wire from the jaws extends through the coil and is attached to the spool while the coil is attached to the central shaft of the handle. Movement of the spool relative to the central shaft moves the pull wire relative to the coil and thus articulates the jaws at the distal end of the coil. In use, the jaws and coil are inserted through a flexible endoscope which is already in place in the patient's body. The surgeon guides the coil and jaws to the biopsy site while a nurse holds the handle. When the surgeon has located the jaws at the appropriate place, the nurse is instructed to operate the handle to articulate the jaws and grasp a biopsy sample. At the conclusion of the biopsy procedure, the entire forceps apparatus is either disposed of or sterilized for re-use.
The known endoscopic biopsy forceps devices of the art have the drawback that the jaws wear out long before the useful life of the handle has expired. Thus, the entire instrument must be discarded when it is only a small portion of the instrument which is inoperative.
Co-assigned parent application Ser. No. 08/016,596 discloses endoscopic instruments having detachable proximal handle and distal portions. These instruments have a distal assembly insertable and removable from a proximal handle assembly in one step actions. The distal assembly includes a tube, end effectors coupled to the tube, and a push rod coupled to the end effectors and slidable through the tube. The proximal handle assembly includes a tube sleeve for receiving the tube, manually operable actuating means, and a latch for coupling the push rod to the actuating means. The tube sleeve is provided with a ball or blade lock for holding the tube securely in place and the tube is provided with a circumferential groove for engaging the ball or blade lock. The latch is spring loaded, hinged, and has an inclined surface for quick coupling with the push rod and an unlatching surface which when biased by an unlatching member uncouples the push rod. The push rod is provided with a mating tip which engages the latch so that the manually operable actuating means causes reciprocal movement of the push rod within the tube to operate the end effectors. Coupling and uncoupling the proximal and distal assemblies is quick, one step, and substantially automatic.
A biopsy forceps device with detachable proximal handle and distal portions is also known and described in U.S. Pat. No. 4,763,668 to Macek et al. It is a disadvantage of the Macek et al. detachable biopsy forceps device that attachment and detachment of the proximal and distal portions requires the screwing in and out of screws and the rotation of a sleeve which makes the attachment and detachment procedures cumbersome. Indeed, no endoscopic instrument devices presently are known (except for that disclosed in the parent application hereto), which have a substantially one step coupling and decoupling mechanism.